Reduction mill



Spt- 5 1939. G. F. AlNsA f 2,171,526

REDUCTION MILL Filed April 1, 19:55

A602e E 6/ 18/ I N l 'EN TOR.

2o HUH..." BY ff@ 47 PatentedV Sept. 5, 1939 amaze .REDUCTION -MILL George Foye Ainsa, San Francisco, Calif., u-

signor of live-eighth to Dolores G. Ainsa,l

Berkeley, Calif.

,Applicationplil 1, 1935, Sel'la1`N0.`l4,012

The present invention relates generally to a reducing mill of the type in which an agglomerate of loose and lumpy material is reduced or pulverized by a rubbing action between the particles 5 thereof, and more particularly to an improved form of mill wherein the partic les of the agglomerate are projected by centrifugal force against a stationary or rotating impact receiving member to thus eifect a reduction of the agglomlu erate by impact operation.

An object of the present invention is to provide areduction mill for reducing and pulverizing an agglomerate which operates on the im` pact principle to reduce the agglomerate to pow- ,ib dered form.

Another object of the present invention is to provide a reduction mill wherein the larger particles of the agglomerate will be reduced and disintegrated in a continuous manner by interim.-

;'0 paction created by centrifugal force.

Another object of the present invention is to provide in a reducing mill of the above character means for returning the unreduced particles of the agglomerate to the reducing elements of the 5 mill and separating the finer particles therefrom by a process of flotation.

Another object of the present invention is to provide a reducing mill which is an improvement upon the mill illustrated and described in my cow pending application for patent, Serial Number 692,073, led October 4, 1933, and entitled Attrition mill.

In the art to which the present invention re- ,lates there has been devised a large number o f 5 mills for reducing ores and other agglomerate by retaining portions thereof in a receptacle by centrifugal force and causing a mass of agglomerate thus held to rub against a second stationary or relatively movable mass of the agglomerate. In reducing mills of this character the agglomcrate is reduced solely by a rubbing action which takes place between the relatively movable particles of the agglomerato as it travels under the influence of centrifugal force and passes o ut of .the mill between grinding rings disposed about the periphery of the entrifugally operating rotor elements. Such a vreducing action .requires the exertion of a high pressure between the particles and consequently a considerable amount of power 0 is necessary 'for satisfactory results. Therefore,

it isa lfurther object of the present invention to provide an improved reduction mill in which the Y particles will be thrown by centrifugal force against an impact member and against each 6 other and thus reduced by impact action withment until the agglomerate is reduced to the de- 10 sired degree of fineness. after which the finely divided agglomerate is conducted away from the mill by flotation or other means.

For a better understanding of the invention and the mode of operation reference should be had to v the accompanying drawing wherein there is shown, by way of illustration and not of limitation, a preferred embodiment thereof. Y In the drawing wherein like numerals designate like parts throughout the several views;

Figure 1 is a side elevation, partially in section, showing a reducing mill constructed in accordance with this invention,

Figure 2 is an end elevation, with parts broken away and in section, taken along line II--II of g5 Figure 1, and

In Figure 1 of the drawing there is illustrated 30 in its entirety a mill, constructed in accordance l with this invention, which is particularly adapted to the reduction of loose and lumpy material, such as ores, cement, rock, clay and the like. As here shown, the lvarious elements of the mill are mounted in associated relation upon a suitable structural iron frame Il having a pedestal II at one end upon which there is journalled a centrifugally operating agglomerate throwing bowl-like rotor element I2, and at the other end of the-40 frame Ill there is a suitable platform arrangement I3 to facilitate the feeding of the material to be reduced to the mill, as will hereinafter appear. The centrifugal agglomerate throwing rotor IZ- is carried by a horizontally disposed shaft I4 45 which is journalled in bearings I5 and driven through a belt I6 by anelectric motor Il. Between the pedestal II and the platform I3 the I frame l0 is adapted to support a rotatable drumlike housing which isy here designated generally by the numeral I8. This housing I8 is provided at its ends with rails I8 and 20 that engage and ride upon spaced supporting rollers 2l and 22 in a manner well understood in the art. Between the rails I9 and 2l the rotatable housing I8 is 55 equipped with an annular driving rack 23 which in cooperationv with a spur gear 24 upon the end of the shaft of a motor 25 is adapted to provide a driving means therefor.

The rotatable housing I8-has a portion 26 of reduced diameter which extends over the centrifugal rotor element I2 and'this reduced portion carries an impact receiving lining 21 which in this ligure of the drawing is shown as consist- Y ing of a plurality of comparatively heavy annular wear-resistant rings 28. The rings 28 fit snugly within the reduced portion 26 and are `remove-y ably secured therein by means of tie-rods 28 so that they may be conveniently removed and infrom the centrifugal rotor II will be subjected to y the most wear, while the rings 28 removed from this area will receive little or no wear, and therefore with this arrangement it is possible to avoid a. renewing of the entire impact receiving lining 21 within the portion 28, by merely rearranging the rings 28 and thus renew only the particular area which has received excessive wear. In accordance with another aspect `of 'this feature of my invention, it is possible to provide rings having' good wear-resistant characteristics at the wear receiving region and use other and cheaper rings at the other points where the wear is not great.

At the outer end of the housing I8 the portion 26 carries a partially closing flange arrangement 38 that serves. to prevent the escape of the agglomerate-thrown by the centrifugal rotor element I2. The other end of the portion 28l is open and in communication with a relatively larger portion 3I of the. rotatable housing -I8 so that, as the agglomerate is thrown against the impact receiving surface 21, both the reduced andunreduced particles of the agglomerate will be discharged into this larger portion 3I of the housing I8. Arranged about the interior of the larger portion 3l of the housing I8 there is a plurality of agglomerate lifting buckets 32 which serve, as the housing I8 is rotated, to return the unrduced particles of agglomerate to a suitable hopper 33 that is disposed within the housing I8 so as to discharge Vsaid agglomerate into the centrifugal rotor element I2. The hopper 33 is preferably mounted upon a projecting portion 34 of the platform structure I3 and it extends through a disk-like balle 35 which is arranged centrally and in spaced relation opposite'the open end of the reduced portion 28 of the drum I8.

The upper half of the disk-like baille 35 is rigidly secured upon the projecting portion 34 Aand the hopper 33 is secured thereto by means of a bracket 38. The lower half of the disk-like baille 35 isl supported so that it vmay swing freely'. about a hinged support 31 to 'permit the discharge of the larger unreduced particles of agglomerate and prevent an excess accumulation of.

confined within the chamber formed bythe wearresistant rings 28 so that its only discharge from this chamber will be by gravity at the lower inner edge of the lextending portion ,28. In the event of an accumulation of an excess of agglomerate, or the presence of a large piece of agglomerate upon the wear-resistant rings 28, the lower half of the baille-like member 35 will swing outwardly upon its hinged support 31 and thus permit the accumulated agglomerate to discharge itself by gravity into the largerportion 3l ofthe housing I8 as the latter rotates.

Extending into the outer end of the housing I8 there is a second hopper 39 which is adapted to discharge agglomerate into the portion thereof which contains the buckets 32. The hopper 38, is adapted to be supplied with agglomerate by any suitable means, for instance, by an operator upon the platform I3 and the buckets 32 are so arranged and inclined within the portion 3l of the housing I8 that they will elevate the agglomerate introduced through this hopper and discharge it into the inner hopper 33 from whichv it will be directed into the centrifugal bowl-like rotor element I2. During this operation the buckets 32 will also operate to return the unreduced agglomerate discharged from the impact receiving surface 21,A as previously described, to the hopper 33,- where it will be subjected to a further action with the newly introducedagglomerate. For the purpose of separating the reduced agglomerate from the unreduced agglomerate the enlarged portion 3I of the housing I8 is provided with a transversely extending baille 40.

'I'his baille 48 is supported Within the housing I8 with its outer edge in spaced relation with the cylindrical wall of the housing I8 and upon the outer edge of this baille 48 there is a truncated conical baille-like member 4I which serves tov prevent the escape of unreduced agglomerate through the spacing thus provided between the baille 48 and the outer wall of the housing I8. In one arrangement; the outer edge of the baille 481s welded tothe buckets 32 so that an extending portion 42 upon each bucket will pro- -ject through the spacing provided between the baille 48 and the outer wall of the enlarged portion 3| of the housing I8. With this arrangement it will be seen that as the agglomerate is velevated by rotation of the housing -I8 the conical reduced agglomerate from the mill by means of a,

circulation of water. In this manner the finer particles of agglomerate will be decanted and/or separated and discharged from the mill by lotation. For the' purpose of providing for such a circulation of water I have shown a water supply pipe 44 hav-lngv a discharge nozzle 45 which is located within the housing I8 immediately over the bucketsA 32, and for the purpose of carrying the discharged and nely reduced agglomerate from the mill proper, I have shown a suitable inclined chute 48 through which the discharged water and reduced agglomerate will flow by grav- 'ity to any point for future treatment;

Cil

envases `In ay milloi' the type contemplated by this in- `ventionthe actionwhich takes place, insofar as thefimpact"featurel of reduction is concerned, is somewhat similar to that which takes place in the well-known Hadsel'mill. However, in the millof the present disclosure the agglomerate Vis thrown, at a high velocity, by centrifugal force against an impact receiving surface and as a result the impact is more intense than is the case in the Hads'el'mill, 'wherein the agglomerate is merely dropped by gravity upon an anvil.

The operation ofthe mill described above is as follows:

When the agglomerate to be reduced is placed in and discharged from the hopper 33 it will be raised by the buckets 32 as the housing I3 rotates and deposited into the hopper 33. The agglomerate thus deposited in the hopper 33 will then be directed into the bowl-like rotor element I2 and from there thrown by centrifugal 'force against the impact receiving lining 21 of the housing I 8 Where it will be broken up and thus reduced. The reduced agglomerate and such agglomerate as has not vbeen reduced to the required flneness will fall .by gravity from the impact receiving lining 21 into the larger portion 3| ofthe housing I3, where the finer particles of the agglomerate will be taken up by the circulation of water and carried out throughthe spacing about the baille 45 and around the truncated coni-` cal portion 4I, where it will be free to flow out of the mill into the chute 45, while the heavier unreduced portion of the agglomerate will remain behind. At this point it should be pointed out that the above action will only take place atl the lower part of the housing I3, and since the circulation of water is unable to carry out the larger particles of the agglomerate at -this point, it will be readily seen that such larger particles of agglomerate as find their way into the space provided around the baille 40 will be directed back into the buckets 32 by the conical baille 4-I as it rotates upwardly out ofthe water. .In order to facilitate this action, I also propose to incline the extending portions 42 of the buckets 32 so that such agglomerate as remains inside of the conicalbaille member 4I will be directed back into the bucketsA 32. f

In the drawing, the housing I3 is shown as proj ,vided with an end closure 41 upon which there is mounted a conically flared member 43 which provides alip-like discharge outlet for the mill. In

order to provide for a variation in the level ofv the water normally retainedwithin the mill for separating purposes, member I3 carriesa suitable ring 49 which may have an inside diameter corresponding to any desired level of water to be retained in the mill. In this connection it may be stated that by varying the level of the water 'centrifugally projected body is proportioned to its mass, the intensity of the impact feature of the mill may be 4variedby increasing or decreasing the speed of the centrifugal rotor I2. The coarseness of the finished material decanted from the housing I 3 may be also controlled by varying the depth and/or the rate of flow of the water therethrough.

In this mill the impactrings 23 are shown as carried by the housing I3 and as rotatable therewith. While this is a preferred arrangement, it is to be understood that the impactrings may be supported in a stationary manner if so desired. However, when these rings are rotated, as shown, the wear upon the inner surfaces thereof will be uniform throughout its circumference and as a result they will last considerably longer than if they are Aheld in a stationary position.

In Figure 3 of the drawing I have illustrated a modified construction for the centrifugal bowllike rotor, which is here designated by the numeral 55, and also a different form of impact surface, which operates somewhat after .the fashion of the impact surface provided in the modified form of mill illustrated in my above identified copending application. As here illustrated, the centrifugal' bowl-like element 53 is provided with an' axially extending flange 5I at its periphery upon which there is secured a wear-resistant ring 52 of highly refractory material. The wear-resistant ring 52 has a cylindrical flange 53 that telescopes with the flange 5I upon the rotor element 50, and extending through the flanges 5I and 53 there is a plurality of dowels 54 which 'are driven into the flanges from the inside of thearotor element. The use of vdovw'els 54 for this purpose (is desirable, even though ynot in all cases absolutely necessary. for the reason that the refractory ring 52 is usually cast andv is of such a highly refractory character that thed'owel holes .cannotbe drilled and therefore must be formed when the ring is cast. With this arrangement the telescoping arrangement of the flanges 5I and 53 serve to center the refractory ring 52 about the axis of rotation and there is therefore no strain upon the dowels 54.

As here shown, the reduced portion 23 of the housing I3 extends over the centrifugal rotor element ina manner similar to that previously Y.

described,l but instead of having its impact receiving surface: formed by a plurality of wearresistantringsn, it hasmeans which will provide for a constantly renewing surface of .agglomerate. The means which provides forl this constantly renewing impact receiving surface of agglomerate. commises in its simplest form nothing more than an inner lining member 55, which is held in concentric vand spaced relation with the cylindrical wall of the reduced'portion 25 of the housing I3. The inner lining member 55 is secured in spacedconcentric relation within' the portion 25 by means of suitable spacing' sleeves 53, through which bolts 51 extend. The inner lining member 55 is comprised of two parts, one being designated by the numeral 53 and the other by the numeral 53.` The members 53 and 55 are of such a width that except for a space 60 provided therebetween, they will provide a lining throughout the axial length of the reduced portion 23. {Ihe space 53 between the portions 53 and 53 of the lining member 55 is so located that it will be substantially and directly in line with the agglomerate which is thrown outwardly under the influence of centrifugal force from the rotor element 5I). ,With this arrangement the sleeves 55 and the bolts 51 arevso spaced that they will prevent the free egress of agglomerate which may eventually find its way between the lining member 53 and the outer wall of the portion 25, and back into the larger portion 3| of the rotatable housing I3. The operation of this form of impact receiving surface may be described as follows:

When the centrifugal rotor element 50 is operate will thus serve to reduce both the thrown and accumulated agglomerate in the area of the space 60 between the lining members 58 and 59. In my aforementioned copending application the retention of the impact surface of agglomerate-is accomplished by rotating the annular portion in which ysaid agglomerate is accumulated at a speed sufficiently high to centrifugally retain a lining of the agglomerate therein, whereas in the present instance I rely entirely upon the rotor 50 throwing the agglomerate at such a rate that the thrown agglomerate will pile up in the space 60 to a depth at least in line with the inner surfaces of the lining members 58 and 59. Under these conditions, it will be readily seen that at the bottom of the spacing 60 there will be no diffilculty in retaining a sufllcient accumulation of agglomerate. However, since the constantly renewing surface of agglomerate will be rotated as the housing |8 turns upon the rollers 2| and 22 and the agglomerate is discharged from the rotor 50 at a substantially uniform rate in all directions, it will be readily understood that a constantly renewing surface of agglomeratel may be retained Within the mill in this manner. In order to reenforce the outer wall of the extending portion 26 of the housing I8 and thus avoid damage thereto at starting and during the period of time when the agglomerate impact receiving surface is being built up, I may insert a reenforcing ring 6l in back ofthe space 60.

' The expressions decanted and flotation, as used above inA describing the action which takes place when the finelyv pulverized agglomerate is discharged from the mill, are intended to include the condition where, due to a lackof water, the` lpulverized agglomerate may be discharged from the mill as a thick muddy mass.

While I have, for thesake of clearness and in order to disclose the invention so that the same can be readily understood, described and illustrated specific devices and arrangements, I desire to have it understood that thisinvention is not limited to the specic means disclosed, but may be embodied in other ways that will suggest themselves, in View of this broad disclosure, to persons skilled in the art. It is believed that this invention is broadly new and it is desired to claim it as such so that all such changes as come within the scope of the appended claims are to be considered as part of this invention.

Having thus described my invention, what I claim-and desire to secure by Letters Patent is- 1. In a centrifugal reducing mill, the combinationl of an open ended bowl-like element adapted to rotate at high speed and centrifugally throw `material to be reduced, hopper means for directing agglomerate to be reduced into said open ended bowl-like element while said element is in rotation, an impact receiving member disposed about the open end of said rotor-element, a rotatable drum-like housing adjacent the open end of said impact receiving member and encircling said hopper for catching the agglomerate discharged from said impact receiving member, said housing having a plurality of buckets disposed labout its inner peripheral surface, an annular separate the reduced from the unreduced ag- 3 glomerate and discharging same at the end of said housing, and means for rotating said drumllke housing whereby the buckets disposed therein will return the unreduced agglomerate to said hopper means. I

' 2. In a reducing min of the character describd comprising a centrifugal agglomerate throwing element and an impact receiving member disposed thereabout, the combination of a drumlike rotatable housing adapted to receive the reduced and unreduced agglomerate discharged from said reducing mill, a partition intermediate the ends of said rotatable housing disposed in spaced relation with the cylindrical surface of said housing, buckets within said housing located at one side of said partition and adapted to return the unreduced agglomerate to said reduction mill, means for' introducing a circulation of water into the bucket containing part of said housing, and a iiarin'g baille extending from said partition and cooperating with said circulation of water to separate the reduced agglomerate from the uny reduced agglomerate.

3. In a reducing mill of the character described comprising a. centrifugal agglomerate throwing element and an impact receiving member disposed thereabout, the combination of a drumlike rotatable housing adapted to receive the reduced and. unreduced agglomerate discharged from said reducing mill, a partition intermediate the ends of said rotatable housing and spaced from the cylindrical surface of said housing to permit the discharge of reduced agglomerate, buckets within said housing located at one side of said partition adapted to return the unreduced agglomerate to said reduction mill, means for introducing a circulation of water into said housing, and a truncated conical baille extending from the spaced outer edge of said partition to prevent the discharge of unreduced agglomerate and cooperating with said circulation of water to separate and discharge the reduced agglomerate from said housing.

4. In a centrifugal reducing mill of the character described, the combination of a rotatable drum having a partition intermediate its ends and spaced from the outer cylindrical wall thereof, to provide a discharge path for reduced agglomerate, an outwardly flaring baille upon one partition around said flaring baiile and discharged from said drum.

5.V In a centrifugal reducing mill of the charn acter described, the combination of a rotatable drum having a partition intermediate its end s and spaced from the outer cylindrical wall thereof, to

provide a discharge path forreduced agglomerate, an outwardly flaring baille upon one`side of said partition extending outwardly at an angle from the outer edge of said partition, buckets arranged within said drum at the other side of said partition for returning unreduced agglomerate to said mill, and means for introducing a circulation of water through said drum, the angle and disposition of said aring baille being such that it will permit the passage of reduced agglomerate therearound and redirect the unreduced agglomerate into vsaid buckets as said drum rotates.

6. An impact receiving chamber for a centrifugal mill of the character described, comprising a rotatable cylindrical drum-like member disposed around a centrifugal agglomerate throwing rotor rotating about a horizontal axis, and a cylindrical member disposed concentric with andin spaced relation with the inside wall thereof, said cylindrical member having a relatively narrow annular opening intermediate its ends and in line with the path of the agglomerate thrown from said centrifugal rotor element, whereby the agglomerate Will be thrown therethrough and build up a constantly renewing surface of agglomerate against which the agglomerate thrown by said centrifugal rotor element will impact.

7. An impact receiving chamber for a centrifugal mill of the character described, comprising a rotatable cylindrical drum-like member disposed around a centrifugally operating agglomerate throwing rotor operating about a horizontal axis, and a cylindrical partition disposed concentric with and in spaced relation with the inside wall of said cylindrical drum-like member, said cylindrical partition having a relatively narrow annular opening intermediate its ends and in line with the path of the agglomerate thrown from said centrifugal rotor element, whereby the agglomerate will be thrown thereinto and build up a constantly renewing surface of agglomerate against which the agglomerato thrown by said centrifugal rotor element will impact.

^ GEORGE FOYE AINSA. 

